High Resolution Köppen‐Geiger Classifications of Paleoclimate Simulations          下载免费PDF全文

Christian Willmes  Daniel Becker  Sebastian Brocks  Christoph Hütt  Georg Bareth 《Transactions in GIS》2017,21(1):57-73

The development and application of an algorithm to compute Köppen‐Geiger climate classifications from the Coupled Model Intercomparison Project (CMIP) and Paleo Model Intercomparison Project (PMIP) climate model simulation data is described in this study. The classification algorithm was applied to data from the PMIP III paleoclimate experiments for the Last Glacial Maximum, 21k years before present (yBP), Mid‐Holocene (6k yBP) and the Pre‐Industrial (0k yBP, control run) time slices. To infer detailed classification maps, the simulation datasets were interpolated to a higher resolution. The classification method presented is based on the application of Open Source Software, and the implementation is described with attention to detail. The source code and the exact input data sets as well as the resulting data sets are provided to enable the application of the presented approach.  相似文献   

Granit und Sial     

Georg Fischer 《International Journal of Earth Sciences》1951,39(1):32-77

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Bau und Entwicklung des Harznordrandes bei Bad Harzburg     

Hans Georg Wunderlich 《International Journal of Earth Sciences》1953,41(1):200-224

Zusammenfassung Konglomeratische Oberkreidesandsteine im Raum Bad Harzburg wurden auf ihren Geröll- und Leitmineralgehalt hin untersucht. Aus der Leitmineralverteilung ergibt sich die stratigraphische Stellung der Emscher- und Senonvorkommen zueinander; aus der Geröllführung geht hervor, daß der Brockengranit bereits im Oberemscher im Erosionsniveau lag und die Aufrichtungszone mesozoischer Gesteine am Harznordrand auch im Schimmerwaldgebiet bis zum Quadratensenon übertage vorhanden war, obwohl sie heute hier nicht mehr zu finden ist. Ursache dieser Erscheinung ist ein Schollenabbruch aus dem Dach des Ilsenburggranits, der an der Wende Granulaten-Quadratensenon erfolgte und zu einer lokalen Überfahrung der Aufrichtungszone geführt hat. Die geologische Neuaufnahme des Paläozoikums nördlich des Ilsenburggranites stellt die heutigen Lagerungsverhältnisse dieses Gebietes klar; sie werden bei der Rekonstruktion der ursprünglichen Lagerung und des Bewegungsvorganges zugrunde gelegt, dessen Ergebnis die teilweise Überdeckung des Vorlandes ist. Ein ähnlicher Vorgang liegt auch am benachbarten Okervorsprung der Harznordrandlinie vor.Unter Berücksichtigung der Ergebnisse neuer Tiefbohrungen im Subherzyn wird eine Auffassung von Ablauf und Ursachen tektonischer Vorgänge in diesem Raum entwickelt, die der herrschenden Meinung in zahlreichen Punkten widerspricht:Eine echte Faltung des Subherzyns im Mesozoikum, die bisher vermutete starke Nordbewegung der Harzscholle und eine ausschließliche Bindung tektonischer Vorgänge in diesem Gebiet an orogene Phasen wird abgelehnt.Auslösender Vorgang aller tektonischen Erscheinungen im Subherzyn ist eine vertikale Differentialbewegung der Harz- und Vorlandscholle, die sich seit Ausgang des Paläozoikums gleichsinnig, aber mit örtlich und zeitlich wechselnder Intensität, abspielt.  相似文献   

Probleme der Lagerstättenlehre     

Georg Berg 《International Journal of Earth Sciences》1922,13(4):349-381

Ohne Zusammenfassung  相似文献   

The first field-based descriptions of pumping-induced saltwater intrusion and upconing     

Georg Houben  Vincent E. A. Post 《Hydrogeology Journal》2017,25(1):243-247

Development of the ideas about the equilibrium between freshwater and saline water has received considerable attention in the literature, but little has been written so far about the earliest scientific works about well salinization. Based on a review of the literature from the second half of the 19th century and the early 20th century, this historical note explores how insights into groundwater abstraction and saltwater intrusion developed, and examples of the earliest field studies are provided. Fundamental research was driven by the need for increasing water supply, but the progress of science did not lead to sustainable management practices everywhere. Research outcomes were shared between scientists of different countries, marking the beginning of coastal hydrogeology as a scientific specialization in the first decade of the 20th century.  相似文献   

Inverse modeling and uncertainty analysis of potential groundwater recharge to the confined semi-fossil Ohangwena II Aquifer,Namibia     

Markus Wallner  Georg Houben  Christoph Lohe  Martin Quinger  Thomas Himmelsbach 《Hydrogeology Journal》2017,25(8):2303-2321

The identification of potential recharge areas and estimation of recharge rates to the confined semi-fossil Ohangwena II Aquifer (KOH-2) is crucial for its future sustainable use. The KOH-2 is located within the endorheic transboundary Cuvelai-Etosha-Basin (CEB), shared by Angola and Namibia. The main objective was the development of a strategy to tackle the problem of data scarcity, which is a well-known problem in semi-arid regions. In a first step, conceptual geological cross sections were created to illustrate the possible geological setting of the system. Furthermore, groundwater travel times were estimated by simple hydraulic calculations. A two-dimensional numerical groundwater model was set up to analyze flow patterns and potential recharge zones. The model was optimized against local observations of hydraulic heads and groundwater age. The sensitivity of the model against different boundary conditions and internal structures was tested. Parameter uncertainty and recharge rates were estimated. Results indicate that groundwater recharge to the KOH-2 mainly occurs from the Angolan Highlands in the northeastern part of the CEB. The sensitivity of the groundwater model to different internal structures is relatively small in comparison to changing boundary conditions in the form of influent or effluent streams. Uncertainty analysis underlined previous results, indicating groundwater recharge originating from the Angolan Highlands. The estimated recharge rates are less than 1% of mean yearly precipitation, which are reasonable for semi-arid regions.  相似文献   

Regional grain size variations in aeolian sediments along the transition between Tibetan highlands and north‐western Chinese deserts – the influence of geomorphological settings on aeolian transport pathways          下载免费PDF全文

Veit Nottebaum  Frank Lehmkuhl  Georg Stauch  Kai Hartmann  Bernd Wünnemann  Stefan Schimpf  Huayu Lu 《地球表面变化过程与地形》2014,39(14):1960-1978

Sediment distribution is investigated applying grain size analysis to 279 surface samples from the transitional zone between high mountains (Qilian Shan) and their arid forelands (Hexi Corridor) in north‐western China. Six main sediment types were classified. Medium scale (10³ m) geomorphological setting is carefully considered as it may play an important role concerning sediment supply and availability. A tripartite distribution of sedimentological landscape units along the mountain to foreland transition is evident. Aeolian sediments (e.g. loess and dune sands) are widespread. They are used to identify aeolian transport pathways. The mU/fS‐ratio (5–11 µm/48–70 µm) among primary loess opposes the two grain size fractions being most sensitive to varying accumulation conditions. The first fraction is attributed to long‐distance transport in high suspension clouds whereas the latter represents local transport in saltation mode. The ratio shows strong correlation with elevation (R² = 0.77). Thus, it indicates a relatively higher far‐traveled dust supply in mountainous areas (>3000 m above sea level [a.s.l.]) compared to the foreland. The contribution of westerlies to high mountain loess deposits is considered likely. Hereby, the influence of the geomorphological setting on grain size composition of aeolian sediments becomes apparent: the contribution from distant dust sources is ubiquitous in the study area. However, the far‐distance contribution may be reduced by the availability of fine sand provided in low topography settings. Plain foreland areas support fine sand deflation from supplying river beds, allowing the formation of sandy loess in foreland areas and intramontane basins. In contrast, high mountain topography inhibits strong sand deflation into loess deposits. Eastern parts of the Hexi Corridor show higher aeolian sand occurrence. In contrast, the western parts are dominated by gravel gobi surfaces. This is attributed to higher sand supply in eastern parts provided by the Badain Jaran Desert and fluvial storages as sand sources. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Modeling reactive transport in non-ideal aqueous–solid solution system     

Haibing Shao  Svitlana V. Dmytrieva  Olaf Kolditz  Dmitrii A. Kulik  Wilfried Pfingsten  Georg Kosakowski 《Applied Geochemistry》2009

The numerical simulation of reactive mass transport processes in complex geochemical environments is an important tool for the performance assessment of future waste repositories. A new combination of the multi-component mass transport code GeoSys/RockFlow and the Gibbs Energy Minimization (GEM) equilibrium solver GEM-Selektor is used to calculate the accurate equilibrium of multiple non-ideal solid solutions which are important for the immobilization of radionuclides such as Ra. The coupled code is verified by a widely used benchmark of dissolution–precipitation in a calcite–dolomite system. A more complex application shown in this paper is the transport of Ra in the near-field of a nuclear waste repository. Depending on the initial inventories of Sr, Ba and sulfate, non-ideal sulfate and carbonate solid solutions can fix mobile Ra cations. Due to the complex geochemical interactions, the reactive transport simulations can describe the migration of Ra in a much more realistic way than using the traditional linear K_D approach only.  相似文献   

The Relation Between Humidity and Liquid Water Content in Fog: An Experimental Approach   总被引：1，自引：0，他引：1  

Stefan Georg Gonser  Otto Klemm  Frank Griessbaum  Shih-Chieh Chang  Hou-Sen Chu  Yue-Joe Hsia 《Pure and Applied Geophysics》2012,169(5-6):821-833

Microphysical measurements of orographic fog were performed above a montane cloud forest in northeastern Taiwan (Chilan mountain site). The measured parameters include droplet size distribution (DSD), absolute humidity (AH), relative humidity (RH), air temperature, wind speed and direction, visibility, and solar short wave radiation. The scope of this work was to study the short term variations of DSD, temperature, and RH, with a temporal resolution of 3?Hz. The results show that orographic fog is randomly composed of various air volumes that are intrinsically rather homogeneous, but exhibit clear differences between each other with respect to their size, RH, LWC, and DSD. Three general types of air volumes have been identified via the recorded DSD. A statistical analysis of the characteristics of these volumes yielded large variabilities in persistence, RH, and LWC. Further, the data revealed an inverse relation between RH and LWC. In principle, this finding can be explained by the condensational growth theory for droplets containing soluble or insoluble material. Droplets with greater diameters can exist at lower ambient RH than smaller ones. However, condensational growth alone is not capable to explain the large observed differences in DSD and RH because the respective growth speeds are too slow to explain the observed phenomena. Other mechanisms play key roles as well. Possible processes leading to the large observed differences in RH and DSD include turbulence induced collision and coalescence, and heterogeneous mixing. More analyses including fog droplet chemistry and dynamic microphysical modeling are required to further study these processes. To our knowledge, this is the first experimental field observation of the anti-correlation between RH and LWC in fog.  相似文献   

Comparison of CloudSat cloud liquid water paths in arctic summer using ground-based microwave radiometer     

Shuang Liu  Georg Heygster  Suping Zhang 《中国海洋大学学报(英文版)》2010,9(4):333-342

Arctic clouds strongly influence the regional radiation balance, temperature, melting of sea ice, and freezing of sea water. Despite their importance, there is a lack of systematic and reliable observations of Arctic clouds. The CloudSat satellite launched in 2006 with a 94 GHz Cloud Profiling Radar (CPR) may contribute to close this gap. Here we compare one of the key parameters, the cloud liquid water path (LWP) retrieved from CloudSat observations and from microwave radiometer (MWR) data taken during the ASCOS (Arctic Summer Cloud Ocean Study) cruise of the research vessel Oden from August to September 2008. Over the 45 days of the ASCOS cruise, collocations closer than 3 h and 100 km were found in only 9 d, and collocations closer than 1 h and 30 km in only 2 d. The poor correlations in the scatter plots of the two LWP retrievals can be explained by the patchiness of the cloud cover in these two days (August 5th and September 7th), as confirmed by coincident MODIS (Moderate-resolution Imaging Spectroradiometer) images. The averages of Oden-observed LWP values are systematically higher (40–70 g m⁻²) than the corresponding CloudSat observations (0–50 g m⁻²). These are cases of generally low LWP with presumably small droplets, and may be explained by the little sensitivity of the CPR to small droplets or by the surface clutter.  相似文献